如何在Xamarin窗体的页面构造函数中从一个页面导航到另一个页面

using Xamarin.Forms;

public class MainPage : ContentPage
{
    public MainPage()
    {
        var nextPageButton = new Button
        {
            Text = "Go to Next Page"
        };
        nextPageButton.Clicked += OnNextPageButtonClicked;

        Content = new StackLayout
        {
            Children = { nextPageButton }
        };
    }

    private void OnNextPageButtonClicked(object sender, EventArgs e)
    {
        var nextPage = new NextPage();
        Navigation.PushAsync(nextPage);
    }
}

public class NextPage : ContentPage
{
    public NextPage()
    {
        Content = new Label
        {
            Text = "This is the next page"
        };
    }
}